Exterior wall structural member for a heat exchanger in a hot-air heater

ABSTRACT

An outside wall panel for a heat exchanger in an air heater furnace wherein the cross-over port structure from the first stage of a heat exchanger is an elongated rectangular inlet into the second stage of the heat exchanger, which has a number of spaced flanges therein for guiding the flow of the products of combustion more evenly in their passage to the outlet of the second stage, the panel having a pair of concave-convex deformations joined together by gradual curves to define a dimple.

May 9,1972

United States Patent Barnes, Jr.

mw 116 Ill 66] 22/ 116 "2 Wmm e c wwm LMo 0 4 246 999 111 3 0 11 983 397 43 365 23 [54] EXTERIOR WALL STRUCTURAL MEMBER FOR A HEAT EXCHANGER IN A HOT-AIR HEATER [72] Inventor: Vernon M. Barnes, Jr., Richmond, Va. Primary Examiner charles J Myhre [73] Texaco Inc., New York, NY.

June 29, 1970 Attorney-Thomas H. Whaley and Carl G. Reis Assignee:

] ABSTRACT An outside wall panel for a heat exchanger in an air heater fur- [22] Filed:

[21] Appl. No.:

nace wherein the cross-over port structure from the first stage [52] US. Cl................. ........126/91 R, 126/106, 126/110 R, f a heat exchanger is an elongated rectangular inlet into the second stage of the heat exchanger, which has a number of spaced flanges therein for guiding the flow of the products of combustion more evenly in their passage to the outlet of the second stage, the panel having a pair of concave-convex deformations joined together by gradual curves to define a dimple.

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4 Claims, 3 Drawing Figures UNITED STATES PATENTS 2,470,860 Parrish....v.,......,.................126/1lO X EXTERIOR WALL STRUCTURAL MEMBER FOR A HEAT EXCHANGER IN A HOT-AIR HEATER BACKGROUND OF THE INVENTION This invention relates generally to hot-air furnace heaters, and particularly to a novel expansion panel for the heat exchange structure therefor, prior to venting the combustion products to the exterior.

Hot-air furnaces are used widely in modern homes. Conventionally, such furnaces include a burner gun assembly firing into a combustion chamber which is joined to some form of radiating means for heating air and which serves as a flue for the discharge of the products of combustion. The radiating means provides a circuitous flow of the hot products of combustion so that a two-stage heat exchanger is suited ideally for heating the air. The air to be heated is provided to a distribution conduit which is spaced around the combustion chamber and radiating means, and adjacent the latter, forms a plenum or distributing space for the ducts leading the heated air to the desired points of reception. Improvements in hot air furnace construction generally are directed to an increase in the efficiency of combustion and/or heat transfer for more even heat distribution and to lower the temperature of the discharged products of combustion. In the commonly assigned, copending application for patent for a Heat Exchange Structure for a Hot-Air Heater, Ser. No. 42,366, filed June 1, 1970 by T. L. Tyson and E. G. Craze, Jr., there is disclosed a more effective heat transfer structure whereby the hot products of combustion are distributed more evenly over the extent of the radiating means or heat exchange surface by means of flow dividers therein, which are parallel to the normal gas flow therethrough, so that the complexity of the gas flow therein is minimized. Thus, the pressure loss in the flow passages is not increased materially. Concomitant with the use of the flow dividers is the use of a novel cross-over port structure to aid in the distribution of the products of combustion in the radiating means.

SUMMARY OF THE INVENTION The invention in general provides for an exterior wall structural member or outside panel of the second stage of the heat exchange surfaces opposite the cross-over port structure between the primary and secondary stages of the heat exchanger, which panel is provided with a pair of concentric deformations to compensate for the unequal heating and for more uniform expansion of the panel in this area.

Accordingly, it is an overall object of this invention to provide for an improved heat exchanger construction.

This and other objects, advantages and features of the invention will become more apparent from the following description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exposed side view of the furnace assembly with the heat exchanger shown in full outline;

FIG. 2 is an isometric view, partly in section, showing the novel construction of the outside panel of the heat exchanger opposite the cross-over port structure; and

FIG. 3 is a partial cross section taken along line 33 of FIG. 2 showing the deformations in the outside panel.

DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to FIG. 1 of the drawings, a hot-air furnace cabinet assembly is disclosed at 1, comprising the air intake section 2 with the air blower assembly 3, and a control assembly at 4 positioned therein. The air distributing conduit 5 leads from the air intake section 2 and surrounds the combustion chamber 6 and the radiating means or heat exchange construction 10, the latter being a two-stage heat exchanger which is joined to the combustion chamber by V-band clamp means 9.

A burner gun assembly 7 fires into the combustion chamber 6 and supports the fuel pump assembly and combustion air blower 8 thereon.

The heat exchanger 10 comprises the first stage 11 having the transition portion lla where the bottom cylindrical structure, which is connected to the circular combustion chamber 6, is changed to a rectangular structure having a closed top 1 lb; and the second stage of the exchanger is shown at 12.

Referring specifically to FIG. 2, partially in section, the two stages of a heat exchanger are shown disclosing the manner in which the cross-over port structure and the support flanges hold the two stages together. The cross-over port structure at 13 is a substantially rectangular vertical inlet into the second stage for the products of combustion leaving the first stage and is flared outwardly to join the inside wall of the second stage. The outlet from the second stage is disclosed as circular at 14 leading to flue 15 (see FIG. 1). This outlet connection and flanges on the opposite panel joined to the cabinet wall (not shown) support the heat exchanger in the cabinet. An inspection door and control air bleed at 16, shown more completely in FIG. 1, and clean-out ports are disclosed at 17, the covers therefor having been omitted for clarity.

The directing flanges 18 are generally parallel to the flow of the products of combustion from the inlet 13 to the outlet 14, these flanges being spaced to provide equal or proportional volumes in the second stage as desired and having bent directional portions at 18a adjacent inlet 13 for directing the flow in a controlled manner around the second stage, and are also bent adjacent outlet 14 at 18b. In addition to the flared cross-over port structure at 13, support flanges at 19, one only being shown at the cut-away section, are used to hold the two stages together. Centrally located, concentric expansion corrugations or deformations in the exterior wall structural member or panel opposite the cross-over port structure are shown at 20a and 20b, the former being convex and having a diameter larger than the length of the cross-over port structure or inlet 13, as seen in FIG. 2, and the latter being concave to form a dimple. This configuration allows for expansion as a corrugated diaphragm to compensate for any unequal heat distribution patterns resulting from the flow out of the crossover port structure. The deformations are shaped so that the expanding metal moves outward through sections that have very gradual radii thereby reducing stress concentrations such as arise when stiffening corrugations of small radii are employed on this structural member. In addition, the shape tends to grow both in and out, lessening the total growth in either direction. When the center is concave, as shown in FIG. 3, the flow path of the combustion products is improved aerodynamically, even though the ends of the flanges 18 adjacent inlet 13 are spaced from the deformation 20a.

FIG. 3 discloses the interior spacing or inside passage 21 between the first and second stages of the heat exchanger. The proportions of this spacing between the exchanger and the cabinet wherein the pumped air is exposed to the heat of the combustion gases in the furnace can be determined by experiment, and likewise the extent of the surface areas of the heat exchanger, the passages and surfaces being chosen in accordance with heating requirements.

Thus, there has been shown and described how an improved expansion panel for a heat exchange structure can be used in a heater which more evenly distributes hot products of combustion to provide for better heating of air and a lowering of flue gas temperatures.

Other modifications and variations of the invention as hereinbefore set forth may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as are indicated in the appended claims.

I claim:

1. In the combination defining a heater construction for providing heated air and including combustion means, a heat exchanger structure comprising wall members defining a pair of concentrically spaced, interconnected heat exchange chambers, the first or inner of said chambers being connected to the combustion chamber of said combustion means and receiving hot products of combustion directly therefrom, the second or outer of said chambers being joined to the first heat exchange chamber by a cross-over port structure defining an inlet thereinto for receiving said products of combustion from said inner of said chambers, and an outlet located in the exterior wall of said outer of said chambers opposite the exterior wall thereof adjacent said inlet for the discharge of said products of combustion from the second heat exchange chamber, said cross-over port structure being substantially rectangular in configuration and extending vertically at the junction between said chambers whereby the flow of said products of combustion into said second heat exchange chamber is more widely distributed adjacent said inlet and itself provides additional heat exchange surface, the improvement comprising the exterior wall of said second heat exchange chamber adjacent said cross-over port structure having a corrugated configuration to counteract heat transfer thereto, said configuration comprising a pair of concentric deformations centered on said exterior wall, the outer deformation being convex and the inner deformation comprising a concave dimple, said deformations being joined together by gradual curves.

2. In the combination as defined in claim 1, said second chamber having a plurality of flow divider flange strips extending from adjacent said inlet to adjacent said outlet for controlled guidance of the flow of said products of combustion therebetween, said flange strips being substantially parallel to the normal flow of said products of combustion in said second chamber to minimize the complexity of said flow therein and to keep the pressure loss at a minimum.

3. In the combination as defined in claim 2, said port structure being flared outwardly from said first chamber to'its junction with said second chamber, said outer deformation having a diameter greater than the length of said port structure.

4. In the combination as defined in claim 3, the spacing between said chambers of said heat exchanger and the surface areas of said chambers being determined by air heating requirements. 

1. In the combination defining a heater construction for providing heated air and including combustion means, a heat exchanger structure comprising wall members defining a pair of concentrically spaced, interconnected heat exchange chambers, the first or inner of said chambers being connected to the combustion chamber of said combustion means and receiving hot products of combustion directly therefrom, the second or outer of said chambers being joined to the first heat exchange chamber by a cross-over port structure defining an inlet thereinto for receiving said products of combustion from said inner of said chambers, and an outlet located in the exterior wall of said outer of said chambers opposite the exterior wall thereof adjacent said inlet for the discharge of said products of combustion from the second heat exchange chamber, said cross-over port structure being substantially rectangular in configuration and extending vertically at the junction between said chambers whereby the flow of said products of combustion into said second heat exchange chamber is more widely distributed adjacent said inlet and itself provides additional heat exchange surface, the improvement comprising the exterior wall of said second heat exchange chamber adjacent said cross-over port structure having a corrugated configuration to counteract heat transfer thereto, said configuration comprising a pair of concentric deformations centered on said exterior wall, the outer deformation being convex and the inner deformation comprising a concave dimple, said deformations being joined together by gradual curves.
 2. In the combination as defined in claim 1, said second chamber having a plurality of flow divider flange strips extending from adjacent said inlet to adjacent said outlet for controlled guidance of the flow of said products of combustion therebetween, said flange strips being substantially parallel to the normal flow of said products of combustion in said second chamber to minimize the complexity of said flow therein and to keep the pressure loss at a minimum.
 3. In the combination as defined in claim 2, said port structure being flared outwardly from said first chamber to its junction with said second chamber, said outer deformation having a diameter greater than the length of said port structure.
 4. In the combination as defined in claim 3, the spacing between said chambers of said heat exchanger and the surface areas of said chambers being determined by air heating requirements. 